His 10-year-old sister, Christine, sat watching television as their dad prepared for a shift pouring drinks at his Queens tavern. Richard Godkin hugged his oldest daughter, kissed her goodnight, and walked out his front door for the last time.

By the early morning hours of April 11, 1981, his neighborhood bar -- opened six months earlier -- was packed. Among the revelers, authorities say, was a mob wannabe celebrating his 24th birthday.

The party ended with Godkin and his co-owner dead on the barroom floor. Police identified a suspect named Frank Riccardi, the son of a reputed Gambino family bookie.

Riccardi walked out of the bar and into the wind. Two other suspects were eventually collared, but Riccardi became the invisible man.

The Godkin boy grew into a man -- a 6-foot-6 Navy veteran intent on becoming a federal marshal. In August 2001, he achieved his goal and joined the Las Vegas office.

Brian Godkin was 28 now. And Frank Riccardi was still on the lam.

The murder case was now in the hands of a New York City cold-case detective, a dogged investigator determined to find Riccardi. During four years on the case, the detective had become friendly with young Godkin.

One week into his new job, acting on a tip from the detective, Godkin typed a name into a federal database.

Another name popped up on the screen. It took 20 years, but Brian Godkin had tracked down the man accused of killing his father.

In April 1981, the nation was recovering from an assassination attempt on President Reagan. ''Celebration,'' the party anthem by Kool and the Gang, blared from jukeboxes around the city.

It was no different at The Shamrock Bar, a popular joint owned by Godkin and partner John D'Agnese.

Godkin, father of four, married for more than a decade, was working two jobs: days at the Queens Boys Club, nights at the bar. ''A little extra money to make life work,'' his widow, Catherine Godkin, says now.

At about 2 a.m. on April 11, Frank Riccardi's birthday celebration was in full bore -- until a drink was accidentally spilled on his date. Court papers detailed an incident that escalated from innocuous to incendiary.

Frank RiccardiAP

An out-of-control Riccardi was tossed from the bar. ''I will be back!'' he screamed. Twenty minutes later, accompanied by two gun-toting friends, Riccardi returned.

D'Agnese was shot point-blank in the face. His girlfriend Linda Gotti -- the niece of local Mafioso John Gotti -- stared in disbelief with two dozen other patrons. Godkin rushed to his partner's aid, and was mortally wounded by Riccardi.

A suspect was quickly arrested, but his case was dismissed after Linda Gotti inexplicably recanted her identification.

The hunt for a second suspect, Bartolomeo ''Pepe'' Vernace, produced nothing. Riccardi disappeared, too; he was indicted in absentia.

As the years passed, Catherine Godkin made her personal peace: ''I've been past it a long time.''

Brian Godkin wasn't past it. After finishing a stint in the Navy, he became a federal corrections officer, angling for that job as a U.S. marshal.

When the 16-year-old Godkin murder arrived at his desk, one thing immediately jumped out: ''The amount of people in the bar.'' He re-interviewed witnesses, and delved into the life of Frank Riccardi, known as ''Frankie the Geech.''

Riccardi's father was reputed Gambino family loanshark Frank ''Cheech'' Riccardi, who had died in 1979. Mansfield heard rumors that ''Cheech'' was killed by the mob for messing with Gotti's niece.

Mansfield's gut told him young Riccardi was alive and living with his mother.

''I always had this feeling that he was in Florida,'' the veteran detective said. ''Where do retired mobsters go? Florida or Arizona. And my theory was if you find the mom, you're gonna find him.''

Mansfield soon developed information about the third suspect in the bar shooting. In November 1998, 17 years after the slaying, he arrested a very surprised Vernace.

But Mansfield's hunt for Frank Riccardi continued.

Last summer, in Boca Raton, Fla., Anthony Frank Alonzo was living in a posh condominium with his elderly mother. He drove a silver 1999 Mercedes, and worked as a circulation manager for the Sun-Sentinel newspaper.

Alonzo knew nothing about Tom Mansfield, who had spent the last four years viewing mug shots and reviewing computer databases in his search.

The cop clung to his mother-and-son hunch.

In mid-August last year, Brian Godkin -- in New York for his nephew's christening -- called Mansfield with an offer. Godkin had just started with the federal marshal service; could he run any names through its database?

Two days later, Godkin called back from Las Vegas. A sophisticated search engine had kicked back a name that matched phonetically, Lena Santille. She lived in Boca Raton, and her birth date made her a likely match for Riccardi's mother.

Mansfield was intrigued. A check of the Florida address showed Anthony Frank Alonzo, about the same age as Riccardi, was living with Mrs. Santille.

Mansfield showed a driver's license picture of Alonzo to one of Riccardi's high school classmates. No question -- Alonzo was Frank Riccardi.

The detective arrived in Boca Raton on Aug. 20, heading to the Alonzo residence that evening. Mansfield hit the buzzer for apartment 302; the reply came in a thick New York accent: ''Whaddaya want?''

Alonzo was lured downstairs with a phony report of a fender-bender involving his Mercedes. When he arrived, wearing a silk pajama top, Mansfield eagerly greeted him.

''I have to ask you a very important question,'' the detective recalled saying. ''What's your real name?'

''And he goes, 'Frank. Frank Riccardi.'''

Catherine Godkin was with her daughters when she received word of Riccardi's arrest at 8 a.m. on Aug. 21. It was her husband's 56th birthday, and they were headed to put flowers on his grave.

On the phone, Mansfield told her, ''We arrested him, and it was because of Brian.''

Justice in the case remains delayed. Vernace has yet to go on trial; Frank Riccardi finally returned to New York in October, and was ordered held without bail pending trial.

Brian Godkin, now a six-month veteran of the marshals office, was reticent about his work. ''I'm not interested in talking about it,'' he said from Las Vegas. ''I just want to take some time to think about the whole thing.''

Catherine Godkin wasn't surprised by her son's silence. She never knew her son had been thinking about Riccardi for the past two decades.